1. Technical Field
The present disclosure relates to lens systems and, particularly, to a zoom lens system having a short overall length and a high zoom ratio.
2. Description of Related Art
In order to obtain small-sized camera modules for use in thin devices, such as mobile phones, personal digital assistant (PDA), or webcams that can still capture quality images, zoom lens systems with high zoom ratio but short overall length are desired. Factors affecting both the zoom ratio and the overall length of the zoom lens system, such as, the number and state of lenses employed, the power distribution of the employed lenses, and the shape of each employed lens, complicates any attempts at increasing zoom ratios but shortening overall lengths of zoom lens systems. For example, reducing the number of lenses can shorten the overall length of the zoom lens system, but zoom ratio will suffer, conversely, increasing the number of lenses can increase zoom ratio, but increases overall length of the zoom lens system.
Therefore, it is desirable to provide a zoom lens system which can overcome the limitations described.